Baudoin



L. BAUDOIN March 3, 1964 3,123,770

' ELECTRIC INDUCTION WATT-HOUR METER WITH SEPARATE VOLTAGE AND CURRENT MAGNETIC STRUCTURES AND CURRENT FLUX ADJUSTING MEANS 2 Sheets-Sheet 1 Filed Nov. 28, 1960 Pi e12.

Zoo' Ewe/0'01 L. BAUDOIN March 3, 1964' 3,123,770 ELECTRIC INDUCTION WATT-HOUR METER WITH SEPARATE v VOLTAGE AND CURRENT MAGNETIC STRUCTURES AND CURRENT FLUX ADJUSTING MEANS 2 Sheets-Sheet 2 Filed NOV. 28, 1960 fifnsu rwy 1001.; B GOO/0 In mentioned above.

United States Patent Ofilice 3,123,770 Patented Mar. 3, 1964 ELECTRIC EJDUCTION WATT-HUUR METER WITH SEPARATE VOLTAGE AND URRENT MAGNETIC STRUUTURES AND CURRENT FLUX ADJUSTING MEANS Louis Baudoin, Neuilly-sur-Seiue, France, assignor to Compagnie de Construction Electrique, lssy-les-Moulineaux, France, a French compan Filed Nov. 28, 1960, Ser. No. 72,698 Claims priority, application France Dec. 4, 1959 6 Claims. (Cl. 324-137) The present invention relates to disc armature induction watt-hour meters of the kind that comprises two magnetic circuits placed on either side of the disc, one of said circuits being energized through a winding supplied with the voltage of the electric power source, and the other one being energized through a winding traversed by the current delivered by said source. The magnetic voltage circuit comprises a central core and two external or lateral pole members; the current magnetic circuit is U-shaped. The respective fluxes set up in these two magnetic circuits act, in a principal airgap that separates them, on a revolving disc armature whose speed, as is well known, is proportional within certain limits to the current delivered by said source.

In the commonly used watt-hour meters, particularly for domestic use, it is generally accepted that for central cores having a thickness of about 10 and 12 mm., the torque developed on the disc is in the range of from 4 to 5 gram centimeters for a consumption in the voltage winding substantially equal to about 1 watt, tor a number of ampere-turns, developed in the current winding, equal to or exceeding 60, for a normal aluminum disc armature having a diameter of less than 100 mm. and with the magnetic circuit providing an airgap leaving the disc with a play of about 1.5 mm. maximum.

The invention relates to an induction watt-l1our meter of this kind, comprising improvements by means of which it will be possible to increase the torque developed, Without a corresponding increase in the power absorbed by the voltage coil and, while diminishing the number of ampere turns developed in the current winding, this results in decreasing the parasite influence of the self-braking torque which, as known, is proportional to the square of the number of these ampere-turns. Thus, by means of the improvements according to the invention, we

obtain a ratio of developed torque to braking torque of high value which more particularly procures an excellent behaviour of the meter with light loads, as well as for heavy overloads, which may attain a value of several times the value of the nominal current.

The meter, according to the invention, is characterized primarily in that the magnetic voltage or potential and current circuits are such as not to comprise any direct magnetic connecting part and are fixed, in relation to each other, by non-magnetic parts, so that practically the entire line of force of the field produced by the magnetic voltage or potential circuit and the field produced by the magnetic current circuit and passing at the same time through both magnetic circuits, traverses the disc twice.

This means that a meter element thus constituted, which, all things being equal, has a current circuit comprising, for example, ampere-turns, can develop a suilicient torque, at least of the same order of magnitude as that It is possible, in these conditions to associate with the electro-motor thus produced, a normal current magnetic circuit, comprising a relatively reduced number of ampere-turns, so as to obtain a normal motor torque with a self-braking torque acceptable at heavy overloads.

A second characteristic of the invention, which is interlinked with the first one, and which can only be used owing to gains in output obtained by this first characteristic, is seen in the arrangement of a supplementary airgap (or several airgaps, hereinafter designated airgap, to simplify the description) inserted in the magnetic current circuit and concerning practically the latter only.

This supplementary airgap enables a certain number of important advantages to be obtained.

First, this airgap makes possible, with regard to the increase of efiiciency and consequently of the motor torque, to reduce the value of the current field to a suitable extent so as correspondingly to reduce the value of the self-braking torque and consequently to obtain a practically horizontal error curve up to a considerable overload, in comparison with the nominal current.

This air gap also permits regulating arrangements to be produced, which, in conventional meters, are generally made at other sensitive points of magnetic circuits: these arrangements are placed on the magnetic current circuit, while leaving the magnetic voltage circuit with all its efliciency, i.e., while retaining for the flux of this magnetic circuit its optimum value for the consumption required.

In the following description given by way of nonrestrictive example, the attached drawings show:

FIGURE 1 is a general diagram of the magnetic circuits of the meter;

FIGURE 2 shows the relative curves of the voltage and current fields;

FIGURE 3 is a perspective showing of details of the magnetic current circuit.

FIGURE 4 is an exploded perspective view of the electro-motor of the meter.

As shown in FIGURE 1, the watt-hour meter comprises a conventional M-shaped magnetic circuit having a central core 1 and external polar parts or members 2. This magnetic circuit, hereinafter called magnetic voltage circuit is energized by the current passing into a coil or winding 3 and being proportional to the voltage of the power source. It also comprises a magnetic U-shaped circuit 4 with polar parts or members 5 which open outwardly towards the center while forming wedge shaped elements or lips 5a. This magnetic circuit '4, hereinafter called magnetic current circuit is energized by a coil or winding 6 supplied by the current delivered by a source such as a main circuit or by a current proportional to that delivered by said source.

In the air gap 7, a meter disc armature 8 is provided which revolves around the axis 7a of symmetry common to both magnetic circuits.

The effective flux of the magnetic voltage circuit principally closes across the pole members 5 of the magnetic current circuit to return to the polar parts 2 of the magnetic voltage circuit and to a small extent, by a flux attracting part 9 linked up, moreover, magnetically to the polar parts 2.

Likewise, the field of the magnetic current circuit principally closes across the magnetic voltage circuit and to a very small extent by the part 9.

The two magnetic voltage and current circuits do not possess any direct magnetic connection. Moreover, the two magnetic circuits are rigidly connected to each other by non-magnetic parts formed by a support-frame of non-magnetic material, for example, of light cast metal, plastic or any other suitable material. The two magnetic circuits are advantageously attached by non-magnetic metal screws to the support-frame 1%. Said frame 100 can also comprise small securing columns of non-magnetic material. Thanks to this arrangement, the flux issued from the pole surfaces of the magnetic voltage circuit and penetrating into the magnetic current circuit is compelled to pass through the disc 8. This also applies to the flux emanating from the poles of the magnetic current circuit and penetrating into the magnetic voltage circuit. In other words, the entire line of force of the field produced by the magnetic voltage circuit, or the field produced by the magnetic current circuit and passing at the same time into both magnetic circuits, traverses the disc twice.

Since the magnetic voltage and current circuits have no direct magnetic connection, the voltage fiux possesses in magnitude and phase the optimum values for developing a maximum torque with the current flux, more particularly in the parts of the disc respectively situated under the lateral poles of the magnetic voltage circuit, as shown in FEGURE 2, furnishing the field H from voltage coil 3 and field H from current coil 6; by way of information and comparison, the curve H' shows the distribution of the voltage field, obtained in conventional magnetic circuits and considered as normal.

As a result of these arrangements, the efiiciency of the magnetic circuits is increased; this gain is due, in particular, to the action of the field H or voltage field under the poles 2 of the voltage electro-magnet and on the induced currents in the disc by the field H or current field; moreover, the supplementary torque thus set up, without modifying the value of the current field, does not thus modify the self-braking torque and consequently, helps to increase the ratio or developed torque to braking torque.

In the arrangement according to the invention, the magnetic current circuit comprises, in its median part connecting the two poles 4, 5, a supplementary airgap it). This airgap is advantageously situated symmetrically in relation to the axis 7a of symmetry. Its faces are preferably parallel, and it can be placed either perpendicularly to the lines of force of the magnetic flux circulating in the median part (FIGURE 1), or obliquely in relation to these lines of force, as shown in FIGURES 3 and 4.

The presence of this supplementary airgap brings about a certain number of important advantages, as previously stated.

According to this arrangement of the invention, the displacement in the airgap it) of a magnetic part enables the motor torque to be varied in an appreciable manner, without causing any considerable modification of the phase of the current flux in relation to the current; thus, a means is obtained for regulating the meter, in non-inductive load, and it becomes possible wholly or in part to replace the method of regulating generally utilized, by magnetic shunting or displacement of the braking magnet 101 ordinarily used in electric meters.

According to the invention, also the displacement in the airgap ltl, of a non-magnetic conductive part enables the phase displacement to be varied of the current flux in relation to the current without appreciably modifying this flux; we thus have a means to regulate the inductive load.

FIGURES 3 and 4- show a particularly advantageous form of embodiment of the invention permitting these adjustments to be carried out.

In this form of embodiment, the airgap It is inclined thus enabling its end 10a (FIGURE 3) to be situated outside the portions covered by the winding 6 which thus enables an easy introducing and displacement of the regulating members described hereafter.

The regulation in phase (or in non-inductive load) is obtained by displacing a magnetic blade 11 in the airgap 1t) and the regulating of the phase displacement of the current flux in relation to the current (or in inductive load) is itself obtained by displacement of a non-magnetic conductive blade 12 in the same airgap.

The blades 11 and 12 are respectively driven by rollers 13 and 14 which are themselves controlled by operating knobs 15 and 16. A fixed part 17 interposed between 4 the blades 11 and i2 prevents the mutual driving of these blades. This part 17 is carried by flanges 192; 103 of non-magnetic material fixed on the magnetic current circuit 4, which flanges act also as support for the driving rollers 13, i4.

Owing to the airgap it which magnetically separates the polar surfaces 5, it becomes possible to carry the latter to slightly different magnetic potentials, by a very slight shunting of the voltage flux; this result is obtained by means of a pivoting magnetic part 18, in magnetic relation with the flux attracting part 9 the displacement of which causes its leakage reluctances to vary in relation to the poles 5. A means is thus obtained for regulating at light loads.

Finally, he airgap It enables the regulation of a selfbrahing torque proportional to the number of ampereturns developed in the current winding, by displacement of the current coil 6 in relation to this air-gap.

it must be clearly understood that the form of embodiment described is only given by way of example and that various alternatives can be effected as it appears in the following claims and all suitable materials can be put into operation for the purpose.

I claim:

1. In an induction watt-hour meter having a rotary disc armature and including two electromagnets defining first a substantially ti-shaped voltage magnetic circuit provided with the magnetically connected pole members exending substantially in parallel relationship and having pole surfaces situated in a common plane and defining secondarily a current magnetic circuit substantially U-shaped and having pole surfaces in alignment and the pole surfaces of the current magnetic circuit being respectively in part in front of two pole surfaces of said voltage magnetic circuit, said electromagnets further being respectively provided with a voltage coil winding and with a current coil winding, the improved arrangement comprising a nonmagnetic material frame support body to which said voltage magnetic circuit and said current magnetic circuit are rigidly connected to define between their pole surfaces an airgap in which said disc armature moves, said improved arrangement further including the feature of constituting said current magnetic circuit with two independent coopcrating magnetic elements separated by an air gap of uniform thickness, the position of which is such that the magnetic reluctance of each element is substantially equal and at least a fiat selectively manually adjustable electrically conductive member inserted at least in part in said air gap, the arrangement furthermore including a nonmagnetic support and driving means carried by said support to operate said adjustable member.

2. In an induction watt-hour meter having a rotary disc armature and including two electromagnets constituting first a substantially M-shaped voltage magnetic circuit having three magnetically connected pole members extending substantially in parallel relationship and having aligned pole surfaces and constituting secondarily a current magnetic circuit substantially U-shaped and having aligned pole surfaces, said electromagnets further being respectively provided with an alternating voltage supplied winding and with an alternating current supplied winding, an improved structure comprising a conductive nonmagnetic metal body to which said two electromagnets are rigidly connected in such relationship as to have their respective pole surfaces oppositely disposed in front one with the other, these respective pole surfaces delimiting further an air-gap in which said disc armature is inserted fully overlapping said pole surfaces, said current magnetic circuit delimiting further an air gap so that it is thus divided into two separated elements of complementary shape having substantially the same reluctance, Wedge-shaped protruding portions extending one toward the other increasing the surface of the pole surfaces of said current magnetic circuit, said latter pole surfaces being thus placed as to extend in front of the pole surfaces of the voltage magnetic circuit which are laterally disposed and in part in front of the pole surface of said voltage magnetic circuit which is placed between the two other pole surfaces thus compelling the magnetic field created by the voltage winding to pass according to two distinct symmetric paths, each closing two times through the disc armature and the magnetic field issued from the current winding to close also at two occurrences through said disc armature rotating inside said air gap separating the voltage and current magnetic circuits, a magnetic plate magnetically connected to the pole members laterally disposed of said voltage magnetic circuit and inserted between said wedge-shaped protruding portions, a magnetic adjusting member pivotally mounted on said plate and provided with actuating means therefor, and a magnetic member and a nonmagnetic but conductive member both independently adjustable, in part inserted inside said air gap delimited between the two elements constituting the current magnetic circuit.

3. In an induction watt-hour meter having a rotary disc armature and including two electromagnets constituting first a voltage magnetic circuit substantially M-shaped having three magnetically connected pole members extending substantially in parallel relationship and having aligned pole surfaces and constituting secondarily a current magnetic circuit substantially U-shaped and having aligned pole surfaces, said electromagnets further being respectively provided with an alternating voltage supplied winding and with an alternating current supplied winding, an improved structure comprising a conductive non-magnetic metal body to which said two electromagnets are rigidly connected in such relationship as to have their respective pole surfaces oppositely disposed in front one with the other, these respective pole surfaces delimiting an air gap in which said disc armature is inserted fully overlapping said pole surfaces, said current magnetic circuit delimiting further an air gap having parallel walls inclined with respect to the flux path inside said current magnetic circuit thus divided into two separated elements of complementary shape having substantially the same reluctance, wedge-shaped protruding portions extending one toward the other increasing the surface of the pole surfaces of said current magnetic circuit, said latter pole surfaces being thus placed as to extend in front of the pole surfaces of the voltage magnetic circuit which are laterally disposed and in part in front of the pole surface of said volt age magnetic circuit which is placed between the two other pole surfaces thus compelling the magnetic field created by the voltage winding to pass according to two distinct symmetric paths, each closing two times through the disc armature and the magnetic field issued from the current winding to close also at two occurrences through said disc armature, a magnetic plate magnetically connected to the pole members laterally disposed of said voltage magnetic circuit and inserted between said wedge-shaped protruding portions, a magnetic blade and a non-magnetic but conductive blade in part inserted in said air gap having inclined walls and driving members selectively operable for independent adjustment of said blades inside said air gap of the current magnetic circuit.

4. In an induction watt-hour meter having a rotary disc armature and including two electromagnets constituting first a voltage magnetic circuit substantially M-shaped having three magnetically connected pole members extending substantially in parallel relationship and having aligned pole surfaces and constituting secondarily a current magnetic circuit substantially U-shaped and having aligned pole surfaces, said electromagnets further being respectively provided with an alternating voltage supplied winding, and with an alternating current supplied winding, an improved structure comprising a conductive non-magnetic metal body to which said two electromagnets are rigidly connected in such relationship as to have their respective pole surfaces oppositely disposed the one in front of the other, these respective pole surfaces delimiting an airgap in which said disc armature is inserted fully overlapping said pole surfaces, said current magnetic circuit delimiting further an airgap having parallel walls inclined with respect to the flux path inside said current magnetic circuit, said current magnetic circuit being thus divided into two separated elements of complementary shape having substantially an equal reluctance, said current winding being so placed as to at least in part overlap said airgap, one end of the inclined airgap at least being situated outside said current winding, lateral sheets of non-magnetic material for connection of said two elements of the current magnetic circuit, said lateral sheets extending beyond the magnetic circuit to delimit substantially parallel flanges, a magnetic blade and a non-magnetic but conductive blade engaged between said flanges and partly inserted inside said airgap of the current mag netic circuit, a separator carried by said flanges and inserted between said blades, driving rollers provided with control plugs carried by said flanges and disposed for separate actuation of said blades, wedge-shaped protruding portions extending one toward the other increasing the surface of the pole surfaces of said current magnetic circuit, said latter pole surfaces being thus placed as to extend in front of the pole surfaces of the voltage magnetic circuit which are laterally disposed and in part in front of the pole surface of said voltage magnetic circuit which is placed between the two other pole surfaces thus compelling the magnetic field created by the voltage winding to pass according to two distinct symmetric paths, each closing two times through the disc armature and the magnetic field issued from the current winding to close also at two occurrences through said disc armature, a magnetic plate magnetically connected to the pole members laterally disposed of said voltage magnetic circuit and inserted between said wedge-shaped protruding portions.

5. In an induction watt-hour meter having a rotary disc armature and including two electromagnets constituting first a voltage magnetic circuit substantially M-shaped having three magnetically connected pole members extending substantially in parallel relationship and having aligned pole surfaces and constituting secondarily a current magnetic circuit substantially U-shaped and having aligned pole surfaces, said electromagnets further being respectively provided with an alternating voltage supplied winding and with an alternating current supplied winding, an improved structure comprising a conductive non-magnetic metal body to which said two electromagnets are rigidly connected in such relationship as to have their respective pole surfaces oppositely disposed in front one with the other, these respective pole surfaces delimiting an airgap in which said disc armature is inserted fully overlapping said pole surfaces, said current mag netic circuit delimiting further an airgap having parallel walls inclined with respect to the flux path inside said current magnetic circuit, said current magnetic circuit being thus divided into two separated elements of complementary shape having substantially an equal reluctance, said current winding being so placed as to at least in part overlap said airgap, one end of the inclined airgap at least being situated outside said current winding, lateral sheets of non-magnetic material for connection of said two elements of the current magnetic circuit, said lateral sheets extended beyond the magnetic circuit to delimit substantially parallel flanges, a magnetic blade and a non-magnetic but conductive blade engaged between said flanges and partly inserted inside said airgap of the current magnetic circuit, a separator carried by said flanges and inserted between said blades, driving rollers provided with control plugs carried by said flanges and disposed for separate actuation of said blades, wedge-shaped protruding portions extending one toward the other increasing the surface of the pole surfaces of said current magnetic circuit, said latter pole surfaces being thus placed as to extend in front of the pole surfaces of the voltage magnetic circuit which are laterally disposed and in part in front of the pole surface of said voltage magnetic circuit which is placed between the two other pole surfaces thus compelling the magnetic field created by the voltage winding to pass according to two distinct symmetric paths, each closing two times through the disc armature and the magnetic field issued from the current winding to close also at two occurrences through said disc armature, a magnetic plate magnetically connected to the pole members laterally disposed of said voltage magnetic circuit and inserted between said wedge-shaped protruding portions, and a magnetic member pivotally mounted on said magnetic plate and having laterally extending wings projecting towards said two elements of the current magnetic circuit and having actuating teeth engaged by a screw member actuated by means of driving elements carried by said flanges.

6. An induction watt-hour meter according to claim 5, wherein said current coil is adjustable on the electromagnet pertaining thereto to change the relation of the current coil with respect to the air gap between the said two elements of the electromagnet.

References Cited in the file of this patent UNITED STATES PATENTS 1,727,509 Kurz Sept 10, 1929 1,806,331 Callsen May 19, 1931 2,003,939 Indergand June 4, 1935 2,115,589 Pratt Apr. 26, 1938 FOREIGN PATENTS 951,027 Germany Oct. 18, 1956 

1. IN AN INDUCTION WATT-HOUR METER HAVING A ROTARY DISC ARMATURE AND INCLUDING TWO ELECTROMAGNETIC DEFINING FIRST A SUBSTANTIALLY M-SHAPED VOLTAGE MAGNETIC CIRCUIT PROVIDED WITH THE MAGNETICALLY CONNECTED POLE MEMBERS EXTENDING SUBSTANTIALLY IN PARALLEL RELATIONSHIP AND HAVING POLE SURFACES SITUATED IN A COMMON PLANE AND DEFINING SECONDARILY A CURRENT MAGNETIC CIRCUIT SUBSTANTIALLY U-SHAPED AND HAVING POLE SURFACES IN ALIGNMENT AND THE POLE SURFACES OF THE CURRENT MAGNETIC CIRCUIT BEING RESPECTIVELY IN PART IN FRONT OF TWO POLE SURFACES OF SAID VOLTAGE MAGNETIC CIRCUIT, SAID ELECTROMAGNETS FURTHER BEING RESPECTIVELY PROVIDED WITH A VOLTAGE COIL WINDING AND WITH A CURRENT COIL WINDING, THE IMPROVED ARRANGEMENT COMPRISING A NONMAGNETIC MATERIAL FRAME SUPPORT BODY TO WHICH SAID VOLTAGE MAGNETIC CIRCUIT AND SAID CURRENT MAGNETIC CIRCUIT ARE RIGIDLY CONNECTED TO DEFINE BETWEEN THEIR POLE SURFACES AN AIRGAP IN WHICH SAID DISC ARMATURE MOVES, SAID IMPROVED ARRANGEMENT FURTHER INCLUDING THE FEATURE OF CONSTITUTING 